package com.lyz.dataStructure.algorithm.哔哩哔哩2020;/**
 * @Author:759057893@qq.com Lyz
 * @Date: ${Date} 20:10
 * @Description:
 **/

import java.util.*;

/**
 *@Author:759057893@qq.com Lyz
 *@Date: 2019/8/20 20:10
 *@Description:
 **/
public class Main4 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String s = sc.nextLine();
        String[] st = s.split(",");
        int[] nums = new int[st.length];
        for(int i =0;i<nums.length;i++){
            nums[i] = Integer.parseInt(st[i]);
        }
        System.out.println(minNum(nums));
    }

    public static String minNum (int[] arr){
        int tab =0;
        String ss = "";
        ArrayList<Integer> list  = new ArrayList<>();
        tab = arr.length;
        for(int i =0;i<tab;i++){
            list.add(arr[i]);
        }
        Collections.sort(list, new Comparator<Integer>() {
            @Override
            public int compare(Integer ob1, Integer ob2) {
                String s1 = ob1+""+ob1;
                String s2 = ob2+""+ob1;
                return s1.compareTo(s2);
            }
        });
        for(int i :list){
            ss+=i;
        }
        return ss;
    }
}
